<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>div+css布局</title>
    <style>

        .left{
            width: 50%;
            float:left;
        }

        .top{
            height: 160px;
        }
    </style>
</head>
<body>


<div>

    <div class="top">top</div>
    <div>
        <div class="left">left-nav</div>
        <div class="left">right-content</div>
    </div>

</div>



</body>
</html>